what is space/vacuum

[gre]

What is vacuum aka space supposed to be made of? Since vacuum has properties such as impedance, permiability and permittivity, is it considered a media?

[Klaynos]

Space-time is made of urmmm well space-time...There's not analogy you can use really.

 

True vacuum does not exist, this is ruled out by vacuum fluctuations, where particles are constantly popping in and out of existence on very very short time scales.

[gre]

You could consider space-time a media though since it can have properties such as electric permittivity and permeability. True vacuum doesn't contain matter, but that doesn't mean it doesn't exist I don't think.

[Klaynos]

You could consider space-time a media though since it can have properties such as electric permittivity and permeability.

 

Yes, but that doesn't mean it has to be made of anything or similar, it is something special...

 

True vacuum doesn't contain matter, but that doesn't mean it doesn't exist I don't think.

 

There are fundamental quantum mechanical arguments (which have been observed) that show that a true vacuum cannot exist. Vacuum fluctuations happen all the time everywhere.

[granpa]

http://en.wikipedia.org/wiki/Vacuum_energy#Origin

[swansont]

Realize that science is much more geared to answering the question "How does the vacuum behave," as opposed to "what is the vacuum?"

[gre]

What is the difference between space and the zero-point field? Could the two be the same thing?

[Severian]

To answer your original question, the vacuum is defined as the lowest energy state. When constitutes the lowest energy state is still unknown, but if the Stadard Model is correct, then it is more energetically favourable to have a background higgs field than no particles at all.

[north]

What is vacuum aka space supposed to be made of?

 

nothing

 

it is devoid of any substance in the strictess of a a vacuum

 

space is space

 

now what I think your really asking is whether space has anything within it ?

 

of course

 

your confusing space and a vacuum in space

 

they are two seperate things , really

 

 

 

Since vacuum has properties such as impedance, permiability and permittivity, is it considered a media?

 

first define " vacuum "

 

and see if this makes sense towards what you have written above

[gre]

 

first define " vacuum "

 

and see if this makes sense towards what you have written above

 

 

I believe vacuum and space can be considered the same thing.

 

They can also be considered a dielectric medium with certain properties which regulate the speed of light.

 

What I'm wondering now is: How does light travel (or propagate) through this "medium"? I remember reading somewhere that virtual particles interact to propagate light through space, but I can't remember the details.

[granpa]

What I'm wondering now is: How does light travel (or propagate) through this "medium"?

 

it would propagate the same way that the fields of particles propagate. the 'medium' would have to be elastic.

 

edit:however it would not be a simple elastic. to produce the inverse square laws that we see it would have to be quite complex.

Edited March 11, 2009 by granpa

[swansont]

your confusing space and a vacuum in space

 

 

 

first define " vacuum "

 

and see if this makes sense towards what you have written above

 

Actually, I think you are assuming that gre is confusing the two.

 

"Vacuum" has several definitions. The vacuum state and the vacuum I get with a pump, i.e. a physical vacuum, are not synonymous. As Severian has already stated, the vacuum state is the lowest energy level of a system.

 

http://en.wikipedia.org/wiki/Vacuum_state

[Norman Albers]

These days I see spacetime as percolating desire. Remember, physics is relatively the same in different frames, but that does not mean permittivity and permeability are absolutely the same. Quite the opposite is the case. For this reason I dared to write of "thickening of the vacuum". I am currently setting my dreamcatcher for theoretics using what I call null speeds of light, which are what an observer at one gravitational point perceives of light moving at another locale. This vector field becomes imaginary (complex) in different regimes.

Edited March 11, 2009 by Norman Albers

[swansont]

These days I see spacetime as percolating desire. Remember, physics is relatively the same in different frames, but that does not mean permittivity and permeability are absolutely the same. Quite the opposite is the case. For this reason I dared to write of "thickening of the vacuum".

 

If that were the case it seems to me there would be an absolute frame, which you could determine by measuring one or the other. (Their product has to be 1/c^2). Electric and magnetic fields will change in the transform between different states, but that's a very different statement.

[Norman Albers]

I don't see why you say that. Every observer perceives the same SOL in their own locale. The vacuum is thus Lorentz invariant.

[gre]

What is the problem with having 'absolute frames' exactly?

[Norman Albers]

The Michelson-Morley determination that given a plus or minus speed of the Earth at points a half-year apart, there is no such change in the measurement of the SOL. Here is a section I lift from the opening of a paper by Hal Puthoff, where he lays out the Polarizable Vacuum approach to GR. I feel he pulls his punches to say: "Although conceptually straightforward, the curved space-time approach can seem rather

abstract to beginning students, and often lacking in intuitive appeal. During the course of

development of GR over the years, however, alternative approaches have emerged that provide

convenient methodologies for investigating metric changes in less abstract formalisms, and

which yield heuristic insight into what is meant by a curved metric." He goes on to describe a scalar field in which electromagnetic and gravitational responses of space are allowed to change smoothly over space. I am trying to build a construction with, a priori, a complex tensor field.

Edited March 11, 2009 by Norman Albers

[north]

I believe vacuum and space can be considered the same thing.

 

They can also be considered a dielectric medium with certain properties which regulate the speed of light.

 

What I'm wondering now is: How does light travel (or propagate) through this "medium"? I remember reading somewhere that virtual particles interact to propagate light through space, but I can't remember the details.

 

 

 

light propagates through space assuming that the source of the light has not diminshed and also through an atternating wave pattern

 

light alternates between a vertical and horizantal wave pattern

 

both push each other outwards into space

 

its been a long time that I found out about this , so I'm sure somebody will correct me on this , on the details

[gre]

light propagates through space assuming that the source of the light has not diminshed and also through an atternating wave pattern

 

light alternates between a vertical and horizantal wave pattern

 

both push each other outwards into space

 

its been a long time that I found out about this , so I'm sure somebody will correct me on this , on the details

 

You are describing the electromagnetic sine wave.

 

Here is a snip from Wiki (http://en.wikipedia.org/wiki/Electromagnetic_radiation#Properties)

 

"Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarized wave propagating from right to left. The electric field is in a vertical plane, the magnetic field in a horizontal plane."

 

I'm not sure if I believe the "self-propagating" part. Is this accurate?

 

This description is also missing the spin aspect of a photon .. Which I'm not sure even has a physical/ real world representation.

[north]

no , not just a sine wave but also a horizontal wave as well

 

its been to long

[Norman Albers]

Good damn questions from several points of view, and I have one or two that are not orthodox. Light is pretty much a transverse disturbance, no? Electric fields jiggle side to side, and at right angles to this are magnetic fields doing the same. Just for this to be happening, we have to cop to an electric permittivity and its magnetic counterpart. I did a study on photons where I figured out a possible electromagnetic field envelope of a localized wave packet of light, really the most basic field model one could execute. I said, if there is a transverse field disturbance with a Gaussian envelope, like a fat cigar or bullet [[words escape me]] then this implies the vacuum or something is supplying response, and this may be understood as a superconducting sort of thing. We all agreed at the start of electrodynamics, that the vacuum cooks, in some responsive fashion. I allowed an expression on the right-hand-side (RHS) of the Maxwell equation that we usually set to zero. This is a good electrodynamic study. WHAT IS PHYSICS? THE QED light-field is not the same and it shows the broader wave nature of photons, like going through "both slits" of a close pair in a diffraction setup. So maybe light doesn't propagate in the neat little bullets I describe and there is a more subtle essence to the field. I think, however, that at the atomic absorption event, my picture of wave packet is realized. The atom may stably exist at quantized energy levels, and the absorption or emission may be seen as a superposition of the two wave states. This is literally a dipole radiator configuration as expressed in the QM 'dipole radiation matrix element'. At some point I think Nature answers to electrodynamic questions, but the fundamental field is deeper than this.

Edited March 12, 2009 by Norman Albers

[lakmilis]

If that were the case it seems to me there would be an absolute frame, which you could determine by measuring one or the other. (Their product has to be 1/c^2). Electric and magnetic fields will change in the transform between different states, but that's a very different statement.

 

And Norman asked, hmm how can you say that, giving a counter argument.

 

I really would like had you Swansont, given yoru reply.. either to refute the counter argument or not being able to do so.. as to see how you both are coming from on that question. (or ajb, another geometer hihi [internal joke there ajb might get] who has very good evaluations on these kind of questions).

 

Hope to see at least... or as often can be the case.. Norman further answering his own posed questions ;p

 

lak xx

[lifestream]

Well i might have "skipped" some info when i read through(fast). I apologize if its been already discussed.

 

Vacuum in, my opinion, can be determined as some kind of area, small or big that has low consistency of everything (any matter, particles etc) - and is not be same as space.

 

Space at the same time is a lot more. Vacuum is part of it. Space is made of everything (dark matter, black holes, stars nebula's, planets, light, radiation - everything).

 

Also perfect vacuum cant be achieved because of a simple reason - imagine area that has nothing in it - wouldn't whole space try to collapse into it. Similar to exposing lets say small balloon 5km deep in water, it will be crushed when everything around it try's to occupy less dense area.

[Norman Albers]

The darkness of our theoretic understanding is roughly 80%, no? Back to current confusions, observers in one locale have a distinct challenge to understand physics in another.

Edited March 28, 2009 by Norman Albers

[lakmilis]

Ye norman.. I am not looking to see who has the strongest argument or anything but because I see that question you posed to counter as a very good one... and I know swansont to be the one i consider has the generally best answers to criticise a problem (popper style). Whilst you are more open to say but what if... and I just think that a reply there form swansont could help develop that investigation between those two arguments you both provided.